how do they get the counterbalancing concrete blocks onto a crane?

Answer 1

with a crane those big uns that go about 1mile an hour

Answer 2

Some of the answers here deal with climbing cranes and are correct. Non climbing tower cranes however are different.

Let me get this in the right sequence - we have the three biggest free standing cranes in the UK on my project at the moment.

So; The tower "stick" is built up with the "A" frame on the top - that's the bit which sticks above the cab and goes to a point.

My biggest crane on my site is 90m high under hook and installation was done with a 500tonne luffing jib mobile crane from Crane services. This tower crane has a 52m radii and a lifting capacity of around 5.5 tonne dependent on whether Lictronic or traditional control system.

The back jib is lifted up and the tie bars fixed to the "A frame" - this makes a triangle shape if you can imagine it. Then the front jib is lifted up and attached basically at the cab level and then tied to the top of the "A frame" with the tie bars.

From what i recall we already had the couterbalances (concrete blocks you describe) fitted to the back jib on installation.

To give you an idea of weight the maximium weight of the section of the crane is around 15Tonnes. The counterbalances don't weigh much in the grand scale of things, I have'nt my techical details here on our cranes but they are not more than 3 tonnes for all of them in total; 500T mobile luffers can lift this at their extremities easily.

If you really want to know more I would advise you to contact Liebherr cranes or Potain who manufacture most of europes cranes.

Mobile cranes have concrete blocks also, for big mobiles such as the 500t describe above, the counterbalances come on separate vehicles, due to the loadings on the UK roads if they were fixed permanently to the vehicle - and other practicalities also.

These are lifted on by the crane itself and drawn up to the underneath of the counterbalance.

Answer 3

Cranes have the ability to swing their own booms around to unload and attach the counterbalancing weights to itself. Most all counterbalancers are steel and not concrete block.

Answer 4

good question. i saw a programme about erecting cranes. the jib and counterbalances are put onto the main mast while it is still low to the ground. the mast has a special section which is used to hoist the entire jib and counterbalances by one mast-section at a time. Basically, the crane builds itself upwards, starting at the base. HArd to describe it verbally. But this section in the mast hoists it, and then they use the crane itself to insert a mast-piece, then raise it again section by section. Sorry, very badly explained... but great question!!

Answer 5

Its assembled on the beam before the cranes are erected(he he). The way they balance each load is clever by adjusting how far the counterbalance is from the fulcrum of the crance. The further away the counterbalance is the hevier the load that can be lifted.

Answer 6

one of the first parts to go on after the main jib. The crane is then jack up and sections fitted in to increase height. This makes the height adjustable to suit different projects.